Method for the manufacture of viscose rayon



Dec. 2, 1952 K. M. MGLELLAN METHOD FOR THE MANUFACTURE OF VISCOSE RAYON 2 SHEETS SHEET 1 Filed May 29, 1948 KENNETH M. MCLELLAN Ihwentot Cittorncg Dec. 2, 1 2 K. M. MGLELLAN 2 METHOD FOR THE MANUFACTURE OF VISCOSE RAYON Filed May 29, 1948 2. SHEETS-SHEET 2 STO/P/NG STEAM REGENERA T/NG f AFTERTREATlNG LIQUIDS TWATER PUR/FY/NG' A/VD k WASH/N6 STEAM sTsAm a-gfljj DRY/N6 TW/STl/VG AND COLLECT/N6 INVENTOR KENNETH M. ML 1. LA/V ATTORNEY Patented Dec. 2, 1952 ntrnon on THE MANUFACTURE or v scose RA roN Kenneth M. McLellan, Cleveland, Ohio, assignor 'to Industrial Rayon Corporation-,-Cleveland3 Ohio, a corporation of Delaware Applicatiqn May 29, 1948, s e ri al No 3,0,(113

19 clai s.

This invention relates 'to a new and shortened process for the production of viscose rayon fila mentary'material hereinafter sometimes referred to as yarn. Mor "particularly, the invention relates to a new and improved method of processing'jfreshly' extruded viscose yarn at elevated yarn treatmenttemperatures and in a continuous sequence of treatment steps; I

'Inthef conventional methods of manufacturing vis' q ef ia On yarn a' viscose spinning solution is extruded through a spinneret'intoan aqueous coa ulatin bath'in which the a i initially for d. Su h ul tin ba hs' i ua l n a n sulfuric acid'and sodium'sulfate together with minor amount of other materials such as zinc s lfate wh ch in uen etherat of r e e at on Of the yarn; The'freshly extruded yarn thus formed is further regenerated and. processed by either the spool system, the pot system, or the continuous processing system. Ordinarily in each of these system the newly formed yarn, after being Withdrawn from the'coagulating bath, is (1) treated with an acid solution to further i'egenerate the yarn, (2) washed to remove adhering acid,' salts, and various icy-products, ds u o lo e b w her wa hi g leach i e red lQwq'b urthr shin and (5) dri'fii Steps (3) in t) usually being referred to a aftertreatmiit andpurification s ps In ome cases he ar i treated wit a lubricant either before or after drying;

n the's qoisvs 'elm th fre h y ex r ded ar is withdrawnfrom the co gula hat afid'col ec n was P -Qbhin, d 1 1. res lt n ya package is subjected to the above-described processing treatments in a series of batch operations. In the potsystem the yarn is centrifugally collected in a rotating pot or box and loosely wound to he, tom; "of a qu derme b le ak is "cak is then c QYeci'Ir m the dtand subj tt to't e abq cr cseribed "plfdcesslnsst' rs in a series of batch operations.

In th continuous processing system, however, the d s red proses'sin ps' ar nerally D foifmed 'on'a "single layer of theyarn as ittra'vels in a continuo a d unint rrupted s q nce fr n tfeatrqent stage mum-next. T e individual processing steps maybeperformed' on a series of thre dva inefith cad s race de i es o whichthe travelin yarn s ten r oran y stored in a plura t cf gfifiie ly helicalrns The present iventmnprqfing a process for producing visc se n i 'Whic the'p c s time between the 'extrusibn"stage andtlie final drying of the finished yarn is considerabl r duced. In general, this is accomplished by using elevated processing temperatures and by reducing the number of'separate pi'ocessing steps. As a consequence, the present inventioi'i makes possiblethe production of viscose rayon by the conmucus" systempii an apparatus'in whicha smaller number of thread-advancing device are required. The new process also'redu'ces the consumption of c'hemicals'and the'num'be'r of manhours "employed per pound of yarn produced. Thus; substantial savings inequipment and proces'sing costs may beacliieved."""'

In accordance withtheprocess of the invention a viscose spinning solution is extruded into a coagulating bath'an'd the resulting filamentary material is withdrawnfrom the bath in anincornp le'tely' regenerated state; Thematerial is thereafter advanced'on o'ne'or more thread-advancing, thread stoi'a'ge devices the form of a'blurality of generally-he'lical"turns and is subjected to the action" of an'acid." A plurality of consecutive turns "of the filamentary material which are being"'subjected 'to'the action of an acid'are maintained substantiallycontinuously in contact with the thread-bearing'periphery of the device as" shown in the reel" devices-in Figure]. and at least that portion of the devicein contact with a ilurality -o'f su'ch' consecutive "turns is heated to'an elevated"temperature;'whereby the applied aqueous" treating liquids present on the advancing filamentary "material are'heated by the thread-advancing device" as" such liquids spread thereon.

The invention is particularly adaptable to the aqueousprocessing ofanadvancing yarn helix at elevated 'temperatureswh'ere heat losses" are encountered which tendto' cool the yarn helix below the elevatedtemperaturedesired. In accordance with the" present "invention such heat losses, which maybe due to evaporation, "radiation; absorption; etc; are offsetbythe heat'transmitted to'the yarn helix by'the heated thrad advancing device incontact therewith.

In practicing the present invention the viscose spinning solution may bepreparedinthe' usual manner and may be"extr'uded'into the customary type a'cid'or non aci'd coagulatingbath";"'Itis advantageous however toemploy'an 'acid bath. Such acid baths'may'advantageously contain'sulfuric' acid in concentrationsfby' weight, of about 5%"to 15 in association'with approkimately 13% to 25% sodium" sulfate and'other salts such as, for example; zinc sulfate in concentrationsof the orderof'l to5 Minor'arhountsof organic compounds such as glucose orvarioixssurfaceactive materials may alsohe present in theco'agulating bath; 1

' The temperature of the bath may be within the range of 40? to 50.? C. or; rfdesired, considerably higher in the order of 55?to'80"Cr or higher" At higher speeds of withdrawal of the yarn'from the bath, say above inetrs'per' n'iinuteybath te'mperatures above 55 0'. may be emnioyed with considerable advantage.-

The spinnere't may be so nositioned in the coagiilatirig"'bath"that'a neww rcrhieayarrr-iravns through the bath a distancef roiif about inch up to or inches or more, such distance being measured from the spinneret face to the point of intersection of the liquid level of the bath with the yarn leaving the bath. The extent of such bath travel or immersion of the newly formed yarn in the bath depends among other things on the rate of withdrawal of the yarn from the bath. In general the lower immersions are employed at the higher spinning speeds. For example, advantageous results may be derived at immersions of from about 2 to /2 inches or less when employing yarn withdrawal speeds say between about 100 to 170 meters per minute or higher and without any guide or yarn contacting surface positioned between the bath and godet.

In practicing the present invention the yarn is treated on devices of the type that advance and temporarily store the yarn in the form of a plurality of generally helical turns, and, on which the yarn can be wound and stored in such a manner that it is substantially continuously in contact with the thread-bearing periphery thereof. A number of such thread-advancing devices are known to the art. They include devices having, as thread-bearing members, a plurality of drums, rollers, rods, bars and th like which are circularly spaced and on which the generally helical turns of yarn may be in the form of a substantially true helix or in a somewhat distorted helical configuration.

It is found advantageous to employ threadadvancing devices in which the spacing between the thread-contacting surfaces of each device are particularly close. In general such thread-contacting surfaces should be close enough to each other to prevent substantial cooling of the heated yarn in the helix as it travels from one heated thread contacting surface to another, e. g., a unitary, heated reel of the type illustrated in Figure 1.

Advantageous results are also derived where the thread-bearing members are so arranged as to permit the formation of a yarn helix having yarn turns that are spaced a minimum distance apart. Particularly suitable for this purpose are L the unitary thread-advancing devices, 1. e., those having closely spaced, interdigitated thread-supporting members of the type illustrated in Figure 1 on which the traveling yarn describes a generally circular helix. Thus, for example, where a generally circular helix is employed having particularly close turns of yarn, a continuous film of treating liquid may advantageously be formed and maintained thereon, such film spreading over a substantially large circumferential area of the helix. The advantages flowing from such conditions will be evident from the examples and will be pointed out more fully later herein. Unitary thread-advancing reels, i. e., those of the type illustrated in the drawing ar described in Knebusch Patent 2,210,914 and are especially well suited for the process of the present invention.

The yarn helix undergoing the aqueous acid treatment is according to the present process maintained at an elevated temperature. It is especially desirable that any other aqueous treatments of the yarn helix also be maintained at elevated temperatures. Advantageous results may be achieved when the elevated temperatures of the liquids present on the yarn helix are above about C. and especially above about C. Temperatures above about and C. and up to and including the boiling point of the aqueous media present on the yarn helix may be employed with particular advantage. In general,

the higher temperatures are most effective in reducing the treatment time; in reducing the rela tive volume and concentrations of the aqueous media applied; in reducing the dimensions of the heated thread-advancing device, and in improving the character of the final yarn product.

Heat may be supplied to the yarn helix in various ways, such as, for example, by radiation from infra-red ray lamps, steam coils and the like positioned adjacent to or about th thread-advancing device so as to heat both the device and yarn thereon or more advantageously by means of an internally heated thread-advancing device in which a suitably heated fluid, e. g. steam, hot gases, hot solutions, Water, etc., is introduced internally of the advancing device. For this purpose unitary thread-advancing reels, i. e., having interdigitating thread-supporting members such as those described in the Bergmann Patent 2,294,866 may be used with particular advantage.

The acid conditions to which the yarn is subjected while in the form of the advancing helix may be achieved in various ways. Thus an aqueous acid solution may be applied to the yarn after it forms the helix or more advantageously the acid may be carried to the helix by the yarn itself. In either situation it is advantageous to create an aqueous acid zone on the heated yarn helix having a, pH below about 4.5 and preferably having an acid concentration corresponding to between about 0.01% and 5%, by weight, sulfuric acid.

In the latter situation the yarn may be conducted to and initially Wound on the threadadvancing device While still wet with aqueous acid bath liquid or it may be conducted thereto while carrying an aqueous acid solution as a result of a prior independent acid treatment. Where yarn in an acid condition is initially wound on the device a neutral or alkaline aqueous washing medium may be applied to the yarn helix at a suificient distance from the beginning thereof and the applied liquid permitted to flow counter-currently of the advancing helix so as to advantageously create both an aqueous acid zone and a subsequent aqueous washing zone on the yarn helix. Such countercurrent flow may be obtained for example by tilting the advancing device downwardly at the thread take-up end about 5 to 15 from the horizontal.

Alternatively, if desired, instead of depending on the acid carried by and contained in the incompletely regenerated yarn to create the acid zone conditions on the heated yarn helix one or more aqueous acid solutions of various types and of a wide range of concentrations may be delivered directly to the acid zone of the heated yarn helix. Thus acids such as sulfuric, phosphoric, nitric, hydrochloric, and the like may be delivered to the yarn helix in dilute aqueous or relatively concentrated form. In the latter situation the acid may be delivered at very low rates of delivery or even dropwise to an aqueous medium already present on the heated yarn helix so that rapid dilution of the delivered acid would occur. Aqueous acid solutions may, for example, be delivered with advantage at concentrations corresponding to about 0.05 to 15%, by weight, sulfuric acid.

After th treatment of the heated yarn helix with acid and, if desired, with other treating media, any acid, salt, or chemical by-products contained in or carried by the treated yarn may advantageously be washed from the yarn while it is still stored as such heated yarn helix; or, if

desired, the yarn may b washed after it leaves such heated yarn helix and such washing may for example be performed while the yarn is in the form of a second independent heated yarn helix. A regenerated and washed yarn may advantageously be dried whileit is still in the form of the first heated yarn helix or, if desired, it may be dried as a second independent heated yarn helix. It is found particularly advantageous to wash and dry a treated yarn while it is in the same heated yarn helix.

The treated yarn helix may be washed and purified with a variety of washing media. Such washing media may for example consist of water or dilute aqueous alkaline media containing one or more of the following materials; yarn lubricating compositions, surface active materials, etc. It is found especially advantageous to maintain av washingzone on a yarn helix in which at least the medium at the last or end portion of the washing zone is maintained at a pH of between about 6.5 and 11, thereby producing a washed yarn having a similar pH.

In addition, if desired, an aqueous desulfurizing zone may be formed between the acid and washing zones such as for example by the intermediate application of aqueous solutions of suitable desulfurizing agents, i. e. sodium sulfide, tri-sodium phosphate, sodium sulfite, etc. Desulfur-izing zones containing aqueous sodium sulfide solution at concentrations between about 0.05 and 0.7%, by weight, may be employed with advantage.

The various aqueous media applied to and present on the heated yarn helix may, if desired, be restricted to specific areas on the helix so as to prevent intermingling thereof. This may be accomplished by mechanical means or by providing aqueous washing zones after each chemical treatment zone. Advantageously however the liquids in the various zones may be permitted to intermingle and flow with suitable control toward the beginning of the yarn helix.

Where one or more applied aqueous media are permitted to flow toward the beginning of the heated yarn helix both the rates of delivery of the aqueous media to the helix and the flow of the aqueous media present on the helix may advantageously be controlled to better maintain both the size of the areas desired for the respective treatment zones and also the concentration desired for the respective treatment zones.

In general the extent of the zone areas for the various treatments are determined by the treatment times necessary in each zone while the treatment times are dependent among other things primarily on the yarn denier, the concentration of the treating medium in each zone, and the elevated temperature employed.

If desired, the yarn may be stretched before or during the treatment on the heated thread-advancing device. A stretch between about and 50% may be employed with advantage.

The accompanying drawings illustrate several forms of apparatus with which the process of the present invention may be practiced.

Figure 1 illustrates an arrangement in which a single thread-advancing reel is employed to process the yarn. The reel is internally heated and to it is conducted a yarn which has been freshly withdrawn from a coagulating bath by a godet wheel. The yarn is processed and dried on the heated reel and is thereafter collected on a cap-twisting device.

Figure 2 illustrates diagrammatically an arreneereent .2 5; ll l fldr i y n l reels i hi th p se r m a at Over a i of 11in; e dvadr neine eel h n, t an inte a y l eatedreel where it is finally processed and; dried. The dried yarn is also, collected. by a cap-twisting; device.

Eigure 3 is a flow-type illustration of one. of the variqusembodiments-of the process.

The; following examples will serve to. further describe the. invention. For convenience the de-. seription in the examples will make reference to the accompanying drawings, it being under-. and that the invention is not intended to be limited to the specific, details set forth.

Example 1 A 150 denier, filament viscose rayon yarn is produced as follows: A viscose spinning solution containing about 6.5% sodium hydroxide and about 8% cellulose. is prepared in the conventional manner. After being ripened to. an index of approximately 4 (sodium chloride) the. viscose is extruded through the spinneret Il positioned in the. coagulating bath I2 contained in the trough I3, the bath I2 being maintained at approximately C. and containing approximately, by weight, 12% sulfuric acid, 22% sodium sulfate, 1.5%, zinc sulfate and 0.1% of a cationactive agent. The spinning solution is extruded at the rate of about it grams per minute and the newly formed yarn I4 is drawn through about 15 inches of the bath liquid at the rate of about meters per minute by means of the draw-off wheel or godet I5 around which the yarn I4 is wrapped about. one turn. The yarn I4 while still in an incompletely regenerated state and while wet with the acid bath liquid I2 is transferred from the godet I5 to the threadstorage, thread-advancing reel I9 of the type described in Knebusch Patent 2,210,914 and Bergmann Patent 2,294,866. The thread-bearing periphery of the reel I9 is about 5 inches in diameter and about 8 inches in length. The axis of reel I9 is tilted about 10 from the horizontal to cause liquid applied to yarn helix to flow toward the thread take-up end of the reel. The reel I9 is driven at a peripheral speed of about '75 meters per minute whereby the yarn I4 between the godet I5 and the reel I9 is stretched about 25%. Reel I9 is heated internally by introducing steam at about 1 to 2 pounds per square inch gauge pressure through the shaft 20, the steam being exhausted through the concentric shaft 2I. The heat from the steam is conducted through the thread-bearing metal bar members 26 of the reel I9. The yarn advancing on the reel I9 is temporarily stored thereon in a helical package of about 7 to 7% inches long containing about 45 helical turns per inch. About 20 cc. per minute of an aqueousr-oil emulsion at about room temperature is delivered to the helix by each of the tubes 22, 23 and 24 respectively. Tubes 22, 23 and 24 are spaced about 1 to 1 inches apart and tube 22 positioned at about 1 to 2 inches from the beginning of the yarn helix. The aqueous oil emulsion comprises about 0.5%, by weight, oil, the oil containing about of both mineral and vegetable oils and about 30% of sulfonated fatty acid esters. The emulsion is delivered at a pH of about 7.5.

Alternatively tube 22 may be omitted and the total 60 cc. per minute of the emulsion may be applied by either tube 23 or 24 or shared by both tubes 23 and 24. The solutions delivered by each of tubes 22, 23 and 24 intermingle eventually and each contributes in forming a continuous film 25 enveloping most of the circumferential area, of the yarn helix. Film 25 flows toward the thread take-up end of reel 19 and it also envelopes the beginning portion of the yarn helix at which point most of the excess liquid is discharged into the tray 28. Since yarn I4 is wet with or contains the acid bath liquid as it travels to and after it is wound on the reel I9, a, numbe of turns of the yarn helix at the thread take-up side of the reel I9 are in the presence of an aqueous-acid medium. The acidity of the yarn progressively diminishes as the yarn traverses the heated reel and as it is met and washed by the aqueous media in the counterfiowing film 25. The yarn helix emerging from the film 25 is substantially completely regenerated; scoured of sulfur impurities, Icy-products and salts; washed free of acid; and simultaneously lubricated.

The point of application of emulsion from the tube 24 and the spread of the film 25 along the reel are adjusted so that a number of turns of the yarn helix are maintained free of film and excess liquids at the thread-discharge end of reel l9 where the yarn is dried. Under the heating conditions herein specified the yarn is dried by storing such liquid-free yarn for about 30 secends.

The excess or drained liquid 21 dripping from the reel l9 into the trough 28 is slightly acid and it also contains the sulfur impurities and byproducts scoured from the treated yarn. The liquid in such trough may be discarded or reclaimed as desired.

The dried yarn l4 after leaving the reel I9 is conducted through the guide 30 and it is then collected by the cap-twister device 3| into a package 32 as a finished and lubricated yarn product.

The yarn produced in accordance with this example has very desirable strength and elongation properties and is desirably uniform in physical properties and appearance.

Example 2 A 150 denier l filament yarn is produced in the manner and under the conditions described in Example 1 except that 40 cc. per minute of a by weight, sulfuric acid solution at room temperature and free of dissolved salts is delivered throu h delivery tube It and water is delivered through tubes 22, 23, and 24 respectively. 5

The yarn thus produced is also characterized by its desirably uniform physical properties and appearance.

Example 3 In this example the conditions are the same as Example 1 except for the following: The viscose spinning solution is extruded at the rate of about 26 grams per minute into the bath maintained at about 65 C. The formed yarn is drawn through about 1 inch of the coagulating bath at a speed of about 125 meters per minute and the heated reel i9 is driven at a peripheral speed of about 150 meters per minute. The distance of travel of the yarn in the bath is measured as the distance from the face of the spinneret to the point of intersection of the bath level with the yarn. emerging from the bath. About 40 cc. per minute of a 1%, by weight, salt-free, sulfuric acid solution at about room temperature is delivered by tube 22, while water and emulsion at the same rate and temperature are delivered by tubes 23 and 24 respectively. The solutions applied are permitted to intermingle and fiow as a continuous film towards the thread take-up end of the reel in the manner described in Example 1.

Example 4 The procedure of Example 1 is followed with the exception that instead of using the godet IS a preliminary thread-advancin reel is used and the bath-wet yarn I4 is stored thereon for about 40 seconds. The yarn l4 discharged from such preliminary reel is thereafter conducted to the heated reel l9 where it is processed and dried according to the conditions described in Example 1.

Example 5 A 150 denier, 40 filament yarn is produced according to the following described procedure which makes reference to Figure 2 of the drawings. Yarn l4 leaving bath [2 is initially formed under the conditions set forth in Example 1 and is transferred to the thread-advancing reel 40 Where it is stored for about 40 seconds While in a bath-wet condition. The yarn l4 discharged from the reel 49 is then led to the thread-advancing reel 42 where it is stored for about 35 seconds while being treated with about 60 cc. per minute of a 5%, by weight, sulfuric acid solution which is applied at room temperature through delivery tube 4|. The acid liquid discharged from the reel 42 is reclaimed and re-used in making up the coagulating bath 12. The acid treated yarn discharged from the reel 42 is then conducted, while in an acid-moist state, to the heated reel E9 on which it is stored as a helical package having about 40 yarn turns per inch. Reel 19 is internally heated in the manner described in Example 1 and travels at a peripheral speed of about 75 meters per minute. The yarn i4 is stretched between the reel 40 and the reel 42 and again between the reel 42 and the heated reel is imparting total stretch of about Water is applied to the yarn helix on the heated reel is by the delivery tubes 22 and 23 and the aqueous-oil emulsion by the tube 24, each tube delivering about 20 cc. of liquid per minute. The temperatures of the aqueous solutions delivered by the tubes 22, 23 and 24 are at about room temperature. The applied solutions are permitted to intermingle and flow as a continuous film toward the beginning of the yarn helix and the yarn helix otherwise processed and dried on reel 19 under the conditions described in Example 1. The dried yarn discharged from the reel I9 is led through guide and finally collected by the cap-twisting device 31 into package 32.

Example 6 A 150 denier, filament yarn is produced in the manner and under the conditions of Example 5, except for the following: About cc. per minute of water instead of the aqueous acid solution is applied to the yarn helix on reel 42. Such water is delivered at a temperature of about 75 C. The yarn discharged from the reel 42 is then conducted to the heated reel l9 and advanced thereon as a package having between about 60 to yarn turns per inch. A 2.5%, by weight, sulfuric acid solution is applied by tubes 22 and 23 and the aqueous-oil emulsion by tube 24. Each of the tubes is set to deliver about 40 cc. of liquid. per minute and all of the aqueous solutions are delivered at about room temperature.

Example 7 The conditions of this example are the same as Example 6 except that a 1%, by weight, aqueous sulfuric acid solution at about room temperature is applied to the reel 40 by delivery tube 39.

:9 Example :8

A 300 denier 80 filament yarn is produced in the manner and under the conditions of Example except for the "following: About 128 grams per minute of viscose is extruded. Steam is introduced internally of godet 'l 5 through shaft Hand exhausted therefrom through the concentric shaft I8. About50 cc. per minute of a 1%,by weight, salt-free, sulfuric acid solution is delivered by tube "I 6 to theyarnl l onthe godet [5. The yarn treatment temperature on the godet I5 is maintained at,about7'5"C. TubeZZ is set-to deliver about cc. per minute of a 2.5%, by weight, salt-free, aqueous sulfuric acid solution at room temperature while tubes 23 and'ZA are set to deliver water and theaqueous-oil. emulsion, respectively, at the rate of ab'out50 cc. perminute.

Example '9 A 1160 denier-480filamentyarnsuitable'as'tire cord is produced'inthe manner andunder the conditions of Example '6 except ,for "the fOllOW- ing: About 5%, by weight'of zinc sulfate is'employed in the coagulating bath; viscose :is extruded at 100 grams per minuteyand' the yarn is stretched between the reels '40, "4.2 and 519 about The yarn is processed "on a heated reel similar to the heated reell9 but' having'adiameter of about 10 inches. such heated reel at about 20 turns perinch while traveling at a linear speed of about meters ;per minute.

In general as long-as suitable treating zones for the acid, yarn washing-or-other. aqueous treatments are maintained on-the heated yarn'helix, a variety of methods for creating-the respective treatment zones therefrom may be employed. By suitable zones are meant zones which are capable of providingproper'and sufficient treat- "ficient area to provide proper yarn regeneration;

a desulfurizing zone having sufficient strength and area; and a washing; zone thatwi'll produce 4 a washed yarn of "desired "pu'rityandpI-I. :These factors are dependent among other .things on (a) the rates -of*delivery'of"the"various treating liquids to the heated'ihelix; lb) *the;concentrations of the varioustreating liquids .delivered to 'ie yarnhel.ix; and (clthetotal volume of liquid. oapableof being retainedjb'ygand'of adhering to the advancing yarn helix *and "thread-advancing device. In general the-properselection of any combination of the above conditions is dependent among other things primarily on-"the degree. of acidity selected forthe acidzoneand on'the pH desired for the "washed "yarn. As previously statedan acldzone having a'pfl'belowaifi'and a washing zone of "which' at" least thelast 'or end portion is-maintained at a'pH'betweenabout'fifi and 11 may be employed withadvantage.

Thus by properly--correlating the concentraticns and rates I of a delivery of the various treating media delivered to therespective zones anumber of methods for creating-and maintainingsuitable acid and washing: zones are available as follows. For examp1e,.idilute or relatively concentrated aqueous .acid solutions may be delivered tothe acid zone to create either-'averydilu-teora-more concentrated acid. trcatmentzone. ISimilar flexibility is available :with other-yarn regeneratin solutions .that may be. :employed; after. the acid zone. :W'here a ihighly alkaline-zone precedes the washing zone an acidified washing medium may The yarnis stored;on

be delivered to the washingzone with'advantage. Alkaline or acid washing media of varying degrees of alkalinity or acidity may-bedelivered to the washing zone, the degrees of alkalinity or acidity depending on the'alkaline or acid concentration of the yarn entering the washing zone and the extent of interminglingof zones, if any. Further, if desired, the treating liquids applied to the acid or other chemical treatment zones may be delivered eitherdropwiseor atgreater rates'of flow depending of course on the concentrations of the liquids being delivered and the concentrationdesired in each zone. For example in a situation where a relatively concentrated acid solutionis delivered-anda verydi-lute aqueous acid zone is desired it is advantageous to lower the rate of delivery of the ;acid solution, increase therate'of delivery of the washing-medium and in addition-cause the-washing medium to flow from the washing zone into the acid zone. Similar adjustments may be made .when delivering other relatively concentrated solutions and also Where Water orother lagueouswashing media are applied after the acidor other chemical treatment zones. 7

It is generally desirable-to maintain a washing step or. zone that 1 will both remove acid. and i byproducts of yarn regeneration'iromr the-yarn-and also produce a washed yarn having the -desired pH. As previously indicated the washingmedium delivered to the washing zone 'may consist of water alone or of an-aqueousmedium having-an acid or alkaline pH depending primarily onthe pH ofthe yarn entering the lwashing'zone, the pH of the immediately.precedingzone and also on the extent oi-interming-ling, if any, .of-thezones. Various materials may beincorporat-ed into the washing medium .with advantage as will be pointed out hereinafter.

In. general where the. elevated treatment temperature .and the zone areas are fixed an increase in yarn speed is preferably accompanied by an increase in total treating. solutions delivered and an increase in concentration in each zone.

Besides controlling and correlating the p'Hiconditions in the variousaqueous treatmentzones it is likewise desirable to correlate the quantities or rates of deliveryof the. various treating :media applied to the heated yarn helix. In the situations. where the respective treating zones are permitted to interminglesuch delivery control provides both a means for 'controllingandcorrelating the pH conditions and concentrations ineach zone and also for controlling the cxtent of-the respective treatingzoneareas.

In general the present process-,may .be-.practiced with the employmentof relatively. small quantities of aqueous treating solutions. In addition as previously shown waterlon highl diluted and expendable treating solutions mayalso be employed. ,As ,,a consequence .the .process oilers considerable savingsin chemicals, in expenses of reclamation of used treating liquidsand in heat expended.

The minimum rates at which .fone. or more of the various aqueous treat n .solutions may ,be delivered to a heatedyarn helix vary depending to a large extent on the yarn turns per inchin the helix. lngenerallower rates of liquid ydelivery-may be employed with greater numbers'of helical yarntu-rns per inch. Thus at about 5 to "20 turns perinch 'there-maylie-delivered to a heated yarnhelix a total of about or 1000 cc. per minute of the aqueous treating liquidsto maintain a suiiicient zliquld' coverage" of the helix. With: 'reater advantageihowever there maybe employed a circular yarn helix having about 20 to 75 or 20 to 65 turns per inch in which case between 20 and 150 cc. per minute ma give sufficient coverage. The quantities of treating liquid referred to may be apportioned equally for delivery to each treating zone or if desired the major portion thereof may be delivered to the washing zone. As previously indicated increased yarn speeds may with advantage be accompanied by an increase in total solutions applied.

Advantageously the liquids applied to the heated yarn helix may be permitted to cover as large a longitudinal and circumferential area of the helix as possible either by delivering each liquid at a number of points along the helix or by forming an aqueous film on a closely wound circular helix or both. Methods of obtaining treating liquid coverage on a thread-advancing reel are described in the Burkholder et al. Patent 2,272,182.

In general the quantity of aqueous media applied may advantageously be restricted to that quantity which is only slightly in excess of the liquid capable of adhering to, or of being retained on, both the advancing device and the heated yarn helix. The application of excessive quantities results in unnecessary consumption of heat to maintain the yarn at the desired treating temperature.

The period of time during which the yarn in the helix is subjected to the action of an aqueous acid medium or any other aqueous medium present on the helix varies depends not only on the yarn denier, the concentration of the acid zone and the treatment temperature employed but also on the extent of circumferential coverage of the yarn helix by the various aqueous treating media applied. Thus at higher temperatures, with lower deniers and greater liquid coverage of the helix, less treatment time is required. For example, to 90 seconds treatment time may advantageously be employed for each treatment zone when processing a 30 to 450 denier yarn as a circular yarn helix containing between about 20 and 75 turns per inch.

The temperature of the aqueous media being delivered to the yarn helix on the heated device may be equal to, lower or higher than the yarn treatment temperature selected and maintained on the heated device. For practical purposes however it is particularly advantageous to deliver lower temperature aqueous media at about room temperature.

The quantity of heat supplied to the yarn helix and thread-advancing device should, of course, be correlated both with the temperature of such aqueous media being delivered and also with the rate of delivery of such aqueous media in order to maintain the yarn at the elevated yarn treatment temperature desired. For example, where greater rates of delivery of aqueous treating media at say room temperature are employed greater amounts of heat should be supplied to the threadadvancing device.

In this connection it is also found that the temperature of the yarn along the helix may vary with variations in rates of delivery and discharge of liquid along the helix and also with variations in thicknesses of liquid film along the helix. Thus where the device is heated internally by steam say at 1 to pounds gauge pressure and treating liquid is delivered at room temperature, the portions of the heated yarn helix containing the thickest films of liquid may be at temperatures as low as 60 or 70' C. while those portions of the helix having only a thin film of liquid may be at or close to the boiling point of the liquid.

The incorporation of various surface active compounds into one or more of the aqueous media applied to the heated yarn helix was found particularly effective in scouring and removing sulfur impurities and by-products from the yarn undergoing regeneration and washing. Particularly advantageous results are obtained where such compounds are incorporated into a combined aqueous yarn lubricating and washing medium and near-boiling treatment temperatures are employed. The presence of such compounds may also be effective in maintaining the thread-advancing device free of harmful incrustations. Such surface-active compounds may be cationic, anionic, or even non-ionogenic in character. They may for example consist of sulfonated aryl, long chain alkyl, or combination alkyl-aryl substituted compounds; solubilized amines or amides containing aryl or long chain alkyl radicals; high- ].y polymerized ethylene oxide or long chain hydrocarbons modified with polyethylene oxide radicals, etc.

If desired, the surface active compounds may be employed to disperse or emulsify Various yarn lubricants or other materials in the aqueous washing medium applied to the heated yarn helix. The yarn lubricants may for example, consist of mineral, vegetable or animal waxes and oils. Concentrations of the order of 0.01% to 4%, by weight, or greater of the lubricant in water may be employed with advantage. Further, they may .be employed to produce aqueous yarn treating emulsions containing materials such as benzene, toluene, pyridine and the like. Such emulsions may be employed with advantage as effective sulfur removing agents.

As shown in some of the examples herein a newly formed yarn withdrawn from a coagulating bath may with advantage be pretreated in various ways prior to its treatment as a heated yarn helix. These pretreatments may consist of any one or more of the following: (1) a longer setting-up time for the freshly extruded yarn may be provided by prolonging the exposure of the yarn to its entrained coagulating bath liquid, such as for example by storing a bath-wet yarn on a preliminary thread-advancing device for about 0.5 to seconds, (2) the yarn While stored on the same or another preliminary thread-advancing device for about 0.5 to 180 seconds may be treated with water or acid; and, (3) such stored yarn may be preheated while in a bath-wet condition or while it is being treated with water or acid. By employing one or more of the above described pretreatments the extent of yarn regeneration and/or purification prior to its treatment as a heated yarn helix may be readily controlled. Thus considerable flexibility in the process is advantageously provided so as to permit a number of variations in the spinning conditions such as, for example, changing bath formulations, reducing the immersion of the newly formed yarn in the bath, increasing extrusion and processing speeds, increasing the amount of stretch, and increasing the yarn denier.

The aqueous acid solutions applied to the freshly extruded yarn in the various pretreatments above described are of various types having a wide range of concentrations. Thus for example acids such as sulfuric, phosphoric, nitric or hydrochloric and the like may be employed. If desired, the acid solutions ma; have substantially stag-ts the same composition as the acid coagulating bath "or with advantage an acid' coagulating bath compositionwhich has beensuitably diluted with water may be employed. Alternatively such aqueous acid Solutions may contain merely one of the acids mentioned in concentrations greater, equal to or less than that present in the coagulating bath. Where oxidizing acids suchas for example nitric acid areiemployed, however, care must be taken to maintain acid concentrations that will not degrade, theyarn. In'general' aqueous acid solutions havingless dissolved salts than the coagulating bath or preferably "substantially free of salts may 'be employed with advantage. Aqueousacid solutions may, for example, be employed with particular; advantage having acid concentrations corresponding to about 0.05% to 15% ,by weight, sulfuric acid.

It is evident from the foregoing that-yarns jof wi'de denier ranges can, be; prcess1ed at wide ranges of speed in accordance with; the present invention. For examplayarns ranging from the finest textile deniers to the heaviest cords such as the tire cord yarns having deniers, up to 1100, 1650, 72000 and upwards maybe processed by making one or, more adjustments of the various processing conditions described. Yarns having Vdeniers between about 39 and "450 may be 'processed particularly effectively.

Iclaim M; l a

1, A process for henmanufacture of viscose rayon cornprising the steps of extruding a Viscose solution into 1a coagulating bath; With-drawing the resulting filamentary material from said bath in an incompletely regenerated state; advancing said filamentary material in a-plurali-ty of generally helical turns on a thread-storage, threadadvanci g device; heating at least a portion of said advancing'devic-e to a temperature of at least about 75 C., said heated thread-advancing device supplying heat to substantially the full circumference of a plurality of helical turnsof fiIamentary material; applying to said filamentarymateri-al on said thread-advancing device 'a liquid capable of furthering theregeneration of said material; at least abortionof'said liquid present; on said advancing material being "-atiatemperature below that of said heated advancing device, whereby said applied is heated by said threadadvancing device as it spreads thereon.

2.'A "process for the manufacture 0f "viscose rayon comprising the steps of "extruding a viscose: solution into 'a coagulating bath; withdrawingthe resulting, filamentary materialfrom'said bath: in an incompletely regenerated state;"advancing:

s'aid filamentary material ina" plurality of gener-- ally. helical turns on 'a'thread-storage, thread-advancing device, said turns being substantially continuously in contact with said device; heating: at least a'portion of said-advancing device to a; temperature of "at least about 815 C.;sai'd"heated threadadvancing device supplying heat to""substantiallythe full circumference of the thread-- helix thereon; applying to said filamentaryma--v t nj' l m id: thread-a vancing d v iquid capable of furthering theregeneration ,of said 'I h i' li a af amn .qise di id resen 0T1 fm ns nie e fi lrb ing. a a t mp rature below that of said heated advancing device,.

whereby "at least a portion ng said applied liquid is heated "by said thread advancing device as itspreads thereon to a t-niperatureaboveabout rayon comprising the's't'eps' of extruding a viscose;

Boss.

s una t a was an. eb i bath? withdrawing the resulting filamentary material from said bath in an incompletely regenerated state; advancing saidfilamerrtary material in a plurality of gejnerall y helicalturns on athreadstorage, tlireadadvancing device, sai'd'tur'ns bea sa any ecstasy c n a i said device; heating at least'a portion of said advancing device to a 'temprature 'of at least about 5f. Q- .e 'dhe t d e e n vice supplying h eatto substantially the run cirlcum eecaef ecretar es e-en: e y t s i fil mente iea e e s d t a Vvancin'g device an aqueous liquid, the resulting liquid cn -said filamentary'material being capable bf furthering the regeneration of said material; said liquid, at substantially a point of its first weta t with. sa adva c m a s n all aternperature below that of said heated advancing device, whereby-said applied'li'quid is heated by said thread-advancing device as it spreads m mber-H c 4. A pr ss for the manufacture of viscose rayon co? 1 rsingth'e steps of extruding a viscose solution into a coagulating bath; withdrawing the resulting filamentary material from said'b'ath in 'an incompletely regenerated -state; advancing said filamentarymaterial in a'plurality of generally helical turns on a thread-storaga'threadadvancing device -said being substantially continuouslyin contact with said device; heating at least a portion of said advancing device to a temperature of: at'least about C., said heated thread advancing device supplying h'at'to sub- Zstantially the fullcircumference of the threadhelix there on; applying to said filamentary'material on said thread-advancing device an aqueus acid liquid; said liquid, at a point substan- 'tially just prior to as first contact with said advancing material, being at atemperatur'e' below th-at'of said heated advancing device, whereby I temperatureof at least about '75 C., said heated thread-advancing device supplying heat to subl stantially the full circumference of the threadh'elix thereon; applying to said. filamentary material on said thread-advancing device an aque- Uo'us'acid liquid; at'least aportion of said liquid pre'sent on said advancing material being at a ei p rel jbe ewihei 1 s a e advancing device, whereby said applied liquid is heated by said thread-advancing device as it spreads thereon; continuously neutralizing said treated,

acidcontaining fiammsrymtemi and drying :saidmaterial. r V

6. A process for the manufacture of viscose fiaysnccmprisin the steps of extruding a viscose saunas into a coagulatin bath; withdrawing the resulting filamentary material from said bath in an incompletely regenerated state; advancing "said filamentary material in a plurality of gen- "emuy helical turns on a thread-storage; threadjad'vancing device; heating'at least a portion tr said advancing device 'to'a' temperature of at least about 75 C., said heated thread-advancing device having closely spaced thread-contacting surfaces so as to supply heat to substantially the full circumference of the thread-helix thereon; applying to said filamentary material on said thread-advancing device a dilute aqueous acid liquid; said liquid, at a point substantially just prior to its first contact with said advancing material, being at a temperature below that of said heated advancing device, whereby said applied liquid is heated by said thread-advancing device as its spreads thereon; continuously subjecting the resulting treated filamentary material to the action of at least one aqueous treating liquid for the removal of further quantities of residual sulfur-containing impurities from said filamentary material; and continuously drying said treated filamentary material.

7. A process for the manufacture of viscose rayon comprising the steps of extruding a viscose solution into a coagulating bath; withdrawing the resulting filamentary material from said bath in an incompletely regenerated state; advancing said filamentary material in a plurality of generally helical turns on a thread-storage, threadadvancing device, said turns being substantially continuously in contact with said device; heating said device internally and maintaining at least a portion thereof at a temperature of at least about 75 C., said heated thread-advancing device supplying heat to substantially the full circumference of the thread-helix thereon; applying to a portion of the helix formed by said advancing filamentary material an aqueous acid liquid; applying to a subsequent portion of said helix an aqueous liquid having a pH between about 6.5 and 11 and causing said applied liquids to intermingle and flow toward the beginning of said helix; forming an aqueous liquid zone by said applied liquids on said helix and maintaining at least a portion thereof at a concentration corresponding to between about 0.01 and 5.0% by weight sulfuric acid; at least one of said liquids being applied, at a point substantially just prior to its first contact with said advancing material, being at a temperature below that of said heated thread-advancing device whereby said applied liquids are heated by said advancing device as they spread thereon.

8. A process for the manufacture of viscose rayon comprising the steps of extruding a viscose solution into a coagulating bath; withdrawing the resulting filamentary material from said bath in an incompletely regenerated state; advancing said filamentary material in a plurality of generally helical turns on a thread-storage, thread-advancing device, said turns being substantially continuously in contact with said device; introducing steam into the interior of said advancing device and heating at least a portion of said advancing device to a temperature of at least about 85 C., said heated thread-advancing device supplying heat to substantially the full circumference of the thread-helix thereon; applying to a portion of the helix formed by said advancing filamentary material an aqueous acid liquid; applying to a subsequent portion of said helix an aqueous liquid having a pH between about 6.5 and 11 and causing said applied liquids to intermingle and flow toward the beginning of said helix; forming an aqueous acid liquid zone by said applied liquids on said helix and maintaining at least a portion thereof at a concentration corresponding to between about 0.01 and 5.0% by weight sulfuric acid and maintaining a subsequent aqueous liquid zone on said helix at said pH of between about 6.5 and 11; said liquids, at a point substantially just prior to their first contact with said advancing material, being at a temperature below that of said heated threadadvancing device, whereby said applied liquids are heated by said advancing device as they spread thereon.

9. A process for the manufacture of viscose rayon comprisin the steps of extruding a viscose solution into an acid coagulating bath; withdrawing the resulting filamentary material from said bath in an incompletely regenerated state; continuously treating said withdrawn filamentary material with an aqueous acid liquid; conducting said treated filamentary material to, and advancing it in generaly helical turns, on a threadstorage, thread-advancing device while in an acid-wet state, said turns bein substantially continuously in contact with said device; maintaining the advancing material at least at the beginning portion of the resulting thread helix in an acid condition; heating said device internally and maintaining at least a portion thereof at a temperature of at least about 75 C., said heated thread-advancing device supplying heat to substantially the full circumference of the threadhelix thereon; applying to said advancing material after said beginning portion of said helix an aqueous liquid having a pH between about 6.5 and 11 and causing said applied liquid to inermingle and flow toward the beginning of said helix; forming on said helix with said applied liquid a dilute aqueous acid zone having an acid concentration corresponding to between about 0.01 and 5.0% by weight sulfuric acid; said liquid being applied, at a point substantially just prior to its first contact with said advancing material, being at a temperature below that of said heated thread-advancing device, whereby said applied liquid is heated by said advancing device as it spreads thereon.

'10. A process for the manufacture of viscose rayon comprising the steps of extruding a viscose solution into an acid coagulating bath; withdrawing the resulting filamentary material from said bath in an incompletely regenerated state; continously treating said withdrawn filamentary material with an aqueous acid liquid; conducting said filamentary material to, and advancin it in generally helical turns, on a thread-storage, thread-advancing device .while in an acid-wet state, said turns being substantially continuously in contact with said device; maintaining the advancing material at least at the beginning portion of the resulting thread helix in an acid condition; introducing steam into the interior of said advancing device and heatin at least a portion of said advancing device to a temperature of at least about C., said heated thread-advancing device supplying heat to substantially the full circumference of the thread-helix thereon; applying to said advancing material after said beginning portion of said helix an aqueous liquid having a pH between about 6.5 and 11 and causing said applied liquid to intermingle and flow toward the beginning of said helix; forming on said helix with said applied liquid a dilute aq ous acid zone having an acid concentration corresponding to between about 0.01 and 5.0% by weight sulfuric acid and a liquid zone subsequent thereto having a pH between about 6.5 and 11; said liquid being applied, at a point substantially just prior to its first contact with said advancing material, being at a temperature below that of material on a second thread-advancing device,

said turns being substantially continuously in contact with said device; introducing steam into the interior of said second advancing device and heating at least a portion thereof to a temperature of at least about 75 0., said heated threadadvancing device supplying heat to substantially the full circumference of the thread-helix thereon; applying to a portion of the resulting helix formed on said second device a dilute aqueous sulfuric acid liquid; applying to a subsequent portion of said helix an aqueous liquid having a pH between about 6.5 and 11 and causing said applied liquids to intermingl-e and flow toward the beginning of said helix; forming on said helix an aqueous acid liquid zone with said applied liquids and maintaining at least a portion thereof at a concentration corresponding to between about 0.01 and 5.0% by weight sulfuric acid; thereafter removing the resulting treated filamentary material from said second device; continuously advancing said removed filamentary material on a third thread-advancing device, said third device being heated internally with steam to a temperature of at least about 75 C. applying to the advancin material on said third device an aqueous treating liquid for the removal of further quantities of residual sulfur-containing impurities from said filamentary material, said treating liquid having a pH between about 6.5 and ll; said treating liquids, at a point su stantially just prior to their first contact with the advancing material on said heated advancing devices, being at a temperature below that of said heated advancing devices, whereby said applied liquids are heated by said advancing devices as they spread thereon; and continuously drying said treated filamentary material on an internally heated thread-advancing device.

12. A process for the manufacture of viscose rayon comprising the steps of extruding a viscose solution into a coagulating bath; withdrawing the resulting filamentary material from said bath in an incompletely regenerated state; advancing said filamentary material in a plurality of generally helical turns on a unitary thread-storage, thread-advancing reel; heating at least a portion of said reel to a temperature of at least about 75 C., said heated thread-advancing device supplying heat to substantially the full circumference of a plurality of helical turns of filamentary material; applying to said advancing filamentary material an aqueous liquid, the resulting liquid present on said filamentary material being capable of furthering the regeneration of said material, the total amount of liquid being applied to said advancing material being between about 20 and 155 cc. per minute; at least a portion of said liquid present on said advancing material being at a temperature below that of said heated reel, whereby said applied liquid is heated by said reel as is spreads thereon.

13. A process for the manufacture of viscose rayon comprising the steps of extruding a viscose solution into a coagulating bath; withdrawing the resulting filamentary material from said bath in an incompletely regenerated state; advancing said filamentary material in a plurality of generally helical turns on a unitary thread-storage, thread-advancing reel, said turns being substantially continuously in contact with said device; heating at least a portion of said reel to a temperature of at least about 75 C., said heated thread-advancing device supplying heat to substantially the full circumference of the threadhelix thereon; applying to said advancing filamentary material an aqueous liquid capable of furthering the regeneration of said material, the total amount of liquid being applied to said advancing material being between about 20 and cc. per minute; said liquid present on said advancing material, being at a temperature below that of said heated reel, whereby said applied liquid is heated by said reel as it spreads thereon.

14. A process for the manufacture of viscose rayon comprising the steps of extruding a viscose solution into a coagulating bath; withdrawing the resulting filamentary material from said bath in an incompletely regenerated state; advancing said filamentary material in a plurality of generally helical turns on a unitary thread-storage, thread-advancing reel, said turns being substantially continuously in contact with said device; applying to said advancing filamentary material an aqueous acid liquid, the total amount of liquid being applied to said advancing material being between about 20 and 150 cc. per minute; heating said reel internally and maintaining at least a part of the liquid-containing, thread-supporting portion of said reel at a temperature of at least about 75 C., said heated thread-advancing device supplying heat to substantially the full circumference of the thread-helix thereon; said acid liquid, at a point substantially just prior to its first contact with said advancing material, being at a temperature below that of said heated reel, whereby said applied liquid is heated by said reel as its spreads thereon; continuously subjecting the resulting treated filamentary material to the action of at least one aqueous treating liquid for the removal of further quantities of residual sulfur-containing impurities from said filamentary material; and continuously washing and drying said treated filamentary material.

15. A process for the manufacture of viscose rayon comprising the steps of extruding a viscose solution into a coagulating bath; withdrawing the resulting filamentary material from said bath in an incompletely regenerated state; advancing said filamentary material in a plurality of closely spaced helical turns on a unitary thread-storage, thread-advancing reel, said turns being substantially continuously in contact with said device; introducing steam into said reel and heating at least a portion thereof to a temperature of at least about 70 C., said heated thread-advancing device supplying heat to substantially the full circumference of the thread-helix thereon; app-lying to a portion of the helix formed by said advancing filamentary material an aqueous acid liquid; applying to a subsequent portion of said helix an aqueous liquid having a pH between about 6.5 and 11 and causing d pp d iquids to intermingle and flow toward the beginning of said helix, the total amount of liquid being applied to said advancing material being between about 20 and 150 cc. per minute;

forming an aqueous acid liquid zone by said applied liquids on said helix and maintaining at least a portion thereof at a concentration corresponding to between about 0.01 and 5.0% by weight sulfuric acid; said liquids present on said advancing material, being at a temperature below that of said heated reel, whereby said applied liquids are heated by said reel as they spread thereon; continuously subjecting said treated material to at least one other aqueous aftertreating liquid and continuously drying said treated filamentary material on an internally heated reel.

16. A process for the manufacture of viscose rayon according to claim 15 in which the threadadvancing reel is heated to a temperature of at least about 85 C.; in which the applied aqueous liquid consists essentially of water and has a pH between about 6.5 and 11 and forms an aqueous liquid zone on the helix, said zone being maintained at a pH between about 6.5 and 11 and being located subsequent to the aqueous acid liquid zone; and in which the resulting treated filamentary material is continuously dried on the same heated reel.

17. A process for the manufacture of viscose rayon comprising the steps of extruding a viscose solution into a coagulating bath; withdrawing the resulting filamentary material from said bath in an incompletely regenerated state; advancing said filamentary material in a plurality of closely spaced helical turns on a unitary threadstorage, thread-advancing reel, said turns being substantially continuously in contact with said device; introducing steam into said reel and heating at least a portion thereof to a temperature of at least about 75 C., said heated thread-advancing device supplying heat to substantially the full circumference of the thread-helix thereon; applying to a portion of the helix formed by said advancing filamentary material an aqueous acid liquid; applying to a subsequent portion of said helix an aqueous liquid having a pH between about 6.5 and 11 and causing said applied liquids to intermingle and fiow toward the beginning of said helix, the total amount of liquid being applied to said advancing material on said reel being between about 20 and 150 cc. per minute; forming on said helix an aqueous acid liquid zone with said applied liquids and maintaining at least a portion thereof at a concentration corresponding to between about 0.01 and 5.0% by weight sulfuric acid; thereafter removing the resulting treated filamentary material from said heated reel; continuously advancing said removed filamentary material on a subsequent thread-advancing reel heated internally with steam, said subsequent reel being heated to a temperature of at least about 75 C.; applying to the advancing material on said subsequent heated reel an aqueous treating liquid for the removal of further quantities of residual sulfur-containing impurities from said filamentary material, said treating liquid having a pH between about 6.5 and 11, the total amount of liquid being applied to said advancing material being between about 20 and 150 cc. per minute; said liquids, at a point substantially just prior to their first contact with the advancing material on said heated advancing reels, being at a temperature below that of said heated advancing reels, whereby said applied liquids are heated by said advancing reels as they spread thereon; and continuously drying said treated filamentary material on an internally heated reel.

18. A process for the manufacture of viscose rayon according to claim 17 in which the threadadvancing reels are heated to a temperature of at least about C.; in which at least one of the aqueous treating liquids applied to the subsequent heated reel is a dilute aqueous sodium sulfide liquid; and in which the filamentary material is continuously dried on another internally heated thread-advancing reel.

19. A process for the manufacture of viscose rayon comprising the steps of extruding a viscose solution into an aqueous sulfuric acid coagulating bath; withdrawing the resulting filamentary material from said bath in an incompletely regenerated state; conducting said withdrawn filamentary material to, and advancing it in generally helical turns, on a first unitary threadstorage, thread-advancing reel while in an acidwet state; subjecting said advancing material to the action of an aqueous sulfuric acid liquid having an acid concentration less than that of said bath; thereafter advancin said filamentary material on a second thread-advancing reel, said turns being substantially continuously in contact with said device; introducing steam into said second reel and heating at least a portion thereof to a temperature of at least about 85 C., said heated thread-advancing device supplying heat to substantially the full circumference of the thread-helix thereon; applying to a portion of the helix formed by said advancing filamentary material on said second reel a dilute aqueous acid liquid; applying to a subsequent portion of said helix an aqueous liquid consisting essentially of water and causing said applied liquids to intermingle and flow toward the beginning of said helix; forming on said helix an aqueous acid liquid zone with said applied liquids and maintaining at least a portion thereof at a concentration corresponding to between about 0.01 and 5.0% by weight sulfuric acid; thereafter removing the resulting treated filamentary material from said second heated reel and continuously advancing said material on a third advancing reel heated internally with steam to a temperature of at least about 85 C.; applying to the advancing material on said third reel at least one treating liquid comprising a dilute aqueous sodium sulfide liquid and thereafter applying at least one aqueous treating liquid having a pH between about 6.5 and 11, the total amount of liquid being applied to the advancing material on said second and third reels being between about 20 and cc. per minute per reel; said liquids, at the point substantially just prior to their first contact with the advancing material on said heated advancing reels, being at a temperature below that of said heated reels, whereby said applied liquids are heated by said reels as they p d o and continuously drying said treated filamentary material on another internally heated reel.

KENNETH M. MCLELLAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Mothwurf Apr. 4, 1944 

1. A PROCESS FOR THE MANUFACTURE OF VISCOSE RAYON COMPRISING THE STEP OF EXTRUDING A VISCOSE SOLUTION INTO A COAGULATING BATH; WITHDRAWING THE RESULTING FILAMENTARY MATERIAL FROM SAID BATH IN AN INCOMPLETELY REGENERATED STATE; ADVANCING SAID FILAMENTARY MATERIAL IN A PLURALITY OF GENERALLY HELICAL TURNS ON A THREAD-STORAGE, THREADADVANCING DEVICE; HEATING AT LEAST A PORTION OF SAID ADVANCING DEVICE TO A TEMPERATURE OF AT LEAST ABOUT 75* C., SAID HEATED THREAD-ADVANCING DEVICE SUPPLYING HEAT TO SUBSTANTIALLY THE FULL CIRCUMFERENCE OF A PLURALITY OF HELICAL TURNS OF FILAMENT- 